From the first introduction of detachable magazines on firearms, people have been looking for ways to increase magazine capacity. Whether it is drum mags, longer box mags, jungle clips to connect multiple mags together, or other gimmicks, more ammo is always the goal. Well, the German army took a rather unusual approach to this issue in 1942, when it introduced an experimental double-magazine version of the MP40.
The gun was intended for special operations troops who were judged to have a particularly pressing need for more ammo on hand to deal with ambushes and high-intensity close range firefights. The design used a completely stock MP40 and replaced the magazine housing with a redesigned one which held two magazines side by side. The pair of magazine wells was a sliding unit that could move left and right under the receiver. Once one magazine was emptied, the shooter would just press a latch on the front of the housing and slide the unit laterally and inch or so, positioning the second loaded magazine in the path of the bolt. The bolt would still have to be pulled back manually before firing, but given the use of military-style magazine pouches this was still definitely faster than reloading a standard MP40.
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